Enter debugfs ! debugfs -c /dev/mapper/vg1-lv1 There’s another way we can recover all our files without going through the pain of imaging, and simply using an external hard drive large enough to hold the actual data you had on the pool ( in my case roughly 4Tb ). In my case, not possible, my HD is 8Tb, my pools are 10.2Tb. Issue there, you hard-drive needs to be as big as your pool, not just the dataset, since the image resulting willīe as big as the pool data you used. That tells me that the main problem I faced was on the LVM thin provisionning metadata layer ( I did not choose thin provisionning in their UI if you ask ). That being done, for the fun of it, a fsck on the image works perfectly fine and the image is mountable Well, it fails, because I/O error ( probably the famous corruption ? ).ĭdrescue is unavailable, but you can always static compile it from source on any os, and copy it to the NAS, so that gives you an image of your pool to work with should something go wrong. You do need an external hard drive large enough to hold your data.įirst, let’s try to dd /dev/mapper/vg1-lv1 into an external hard drive, since the cachedev is not necessary, we are not gonna do any kind of caching while recovering.
This is not necessary though, since /dev/mapper/vgX-lvY contains your filesystem without that added layer ( and I recommend bypassing it during a recovery anyway, since more layers => more troubles ). ( mdadm assemble, drbd up, lvscan ) for the last cachedevX, you can use /sbin/SSDcacheutil to mount the /dev/mapper/vgX-lvY device to the /dev/mapper/cachedevX entry that Qnap uses to mount the device. Another tool of interest if you want to mount manually their stack EXT4-fs (dm-16): INFO: recovery required on readonly filesystemįor those that wants to go further, /sbin/storage_util is a good tool to use, especially the –sys_startup_p2 and the –stop_storage options. EXT4-fs (dm-9): INFO: recovery required on readonly filesystem The relevant logs: device-mapper: thin: 253:4: switching pool to read-only mode While looking into dmesg, I find that LVM metadata has issues and the LVM pool is mounted read only, you can’t correct the errors if it’s r/o…. So in my case: MDADM RAID5 /dev/md1 DRBD /dev/drbd1 LVM thin provision pool /dev/mapper/vg1-t* LVM subvolume of the pool per ‘storage pool on the UI’ /dev/mapper/vg1-lvX cache device ( without a fstab ) /dev/mapper/cachedevX ext4 It is layers upon layers.īasically, Qnap creates a mdadm raid with your disks, then put drbd with a bogus remote peer on top, then LVM thin provisionning on the drbd device, with lvm subvolumes representing your pools, and then a weird cache system on top of the LVM devices. I will pass you the steps of looking into how QNAP setup the system. Proper copy next time, I know… First, let’s try to understand how it is all setup Yes, I know, data should be backed up, but in this case, snapshots used to backup were also corrupted and problematic. Investigate further, after all it does not make sense that all my data is gone, it was there before the dreaded reboot. After telling me that all data is lost and that they can ’t do anything, I decide to Running fsck many times to the same result => i/o error while writing, then trying to restore snapshots that fails.
Qnap check filesystem windows#
Couple days later, a technician plan a teamviewer session ( thank you throw away vm, I don’t run windows here…. Like a good citizen, called out on qnap support thinking given theĮxtent of the problem would have a way to get back from it. I got hit by the cache ‘data corruption bug’, one day finding all my pools R/O and after a reboot not even able to be mounted.
Qnap check filesystem install#
So QNAP QTS suffered from a data corruption bug when using the NAS ( well, not only one, but that just tells you to migrate your NAS to a better OS if you can, all qnaps with HDMI output shouldīe able to install a proper truenas/unraid/purelinux whatever that is better than their stuff ). Sysadmin qnap ext4 mdadm raid data corruption fsck debugfs recovery The issue
Qnap check filesystem how to#
Qnap QTS had an issue on v5 of their os, creating corruption of the data you store, let’s see how to fix, and how qts works ←Home Blog Resume Webmail Matrix ActivityPub Qnap data corruption bug, support said everything's lost, everything recovered. Qnap data corruption bug, support said everything's lost, everything recovered.
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